It is therefore an object of the present invention to provide a method for actuating an electrically actuated friction brake, with which the braking effect of the friction brake may be selectively influenced in a certain operating point to be able to reliably and easily achieve regulation or control of a required braking effect of the friction brake.
This object is achieved according to the invention in that an actuation energy of the electric motor is determined for the braking operation, and the ascertained actuation energy is determined as the actual actuation energy in the predefined setpoint position of the friction brake, and a setpoint actuation energy is determined with respect to the setpoint position or with respect to a setpoint braking effect from known data concerning the friction brake, and a deviation between the actual actuation energy and the setpoint actuation energy is compensated for by actuating the friction brake. By using the actuation energy, the energy that is introduced into the friction brake during a change from an initial state of the friction brake (released, for example) to a final state of the friction brake (full braking, for example) is evaluated. The manner, and the period of time, in which the final state has been reached plays no role for the energy, so that the energy represents the final state, regardless of how it was reached. A summation (or integral) for determining the actuation energy is relatively stable with respect to individual measuring errors due to using a large number of individual values which may be averaged, which also makes the method very robust with respect to any interferences. The problems with current measurement may be easily avoided in this way. Apart from this, determining the actuation energy is easily achievable with little effort, and there are numerous options for determining the actuation energy of the electric motor, thus allowing great flexibility in carrying out the method. This allows simple, reliable control of the actuation of an electrically actuated friction brake.
By determining the actuation energy actually introduced into the actuation as the actual actuation energy with respect to the setpoint position or with respect to a setpoint braking effect, and comparing to a known setpoint actuation energy to be expected, any deviation may be easily identified and compensated for by actuating the friction brake. At the end of the braking operation, it may thus be easily checked whether the predefined setpoint braking effect due to setting the setpoint position has actually been achieved, and any identified deviation may be corrected.